Lens-fitted film unit with a rapid film winding system

Abstract

A lens-fitted film unit has a film winding mechanism comprising a planetary gear set disposed between a winding knob and a rotary shaft engageable with a spool of a pre-loaded film cartridge to which a film strip at one end is attached. The planetary gear set comprises a sun gear as an integral part of the rotary shaft, a ring gear having a greater number of teeth than that of the sun gear, and at least one planet gear in mesh with the sun gear and the ring gear which revolves around the sun gear by means of rotation of the winding knob and rotates on its own axis so as to increase rotation of the winding knob and transmits the increased rotation to the rotary shaft, and hence the spool, so as thereby to decrease a burden on the user.

What is claimed is: 
     
       1. A film winding mechanism for winding a photographic film strip in a photographic apparatus after exposure, the film winding mechanism comprising: a spool mounted for rotation inside the photographic apparatus to which one end of a film strip is attached;   a spool driving shaft engaged with one end of the spool;   a driving member operable to cause rotation of the spool driving shaft to wind the film strip onto the spool; and   a planetary gear set interposed between and connected to the driving member and the spool driving shaft, the planetary gear set comprising: an immovable ring gear having inward facing teeth, the ring gear being fixed to an exterior of a main body of the photographic apparatus;   a driven sun gear rotatable disposed within the ring gear and attached to the spool driving shaft; and     at least one planet gear, each being meshed with both the ring gear and the sun gear, a rotational axis of each said planet gear being fixed with respect to the driving member;   wherein the driving member, the planetary gear set, and the spool driving shaft are arranged so that rotation of the driving member through a given angular displacement causes rotation of the spool driving shaft through an angular displacement greater than that of the driving member.   
     
     
       2. The film winding mechanism as recited in claim 1, wherein the driving member comprises a manually operable rotary knob disposed entirely outside of the main body of the photographic apparatus. 
     
     
       3. The film winding mechanism of claim 2, further comprising a top boss disposed on an end of the sun gear opposite the spool driving shaft, the top boss being rotatably supported within an aperture disposed in a center of the rotary knob. 
     
     
       4. The film winding mechanism as recited in claim 2, wherein the planet gears are disposed at regular angular intervals, each of the planet gears being rotatable mounted on a carrier shaft disposed on a lower face of the rotary knob. 
     
     
       5. The film winding mechanism of claim 4, further comprising a top boss disposed on an end of the sun gear opposite the spool driving shaft, the top boss being rotatably supported within an aperture disposed in a center of the rotary knob. 
     
     
       6. A lens-fitted film unit containing therein a film strip, a factory pre-loaded empty film cartridge, and a film winding mechanism for winding the film strip into the film cartridge after exposure, the film winding mechanism comprising: a spool mounted for rotation inside the film cartridge to which one end of a filmstrip is attached;   a spool driving shaft engaged with one end of the spool;   a driving member operable to cause rotation of the spool driving shaft to wind the film strip onto the spool; and   a planetary gear set interposed between and connected to the driving member and the spool driving shaft, the planetary gear set comprising: an immovable ring gear having inward facing teeth, the ring gear being fixed to an exterior of a main body of the photographic apparatus;   a driven sun gear rotatable disposed within the ring gear and attached to the spool driving shaft; and     at least one planet gear, each being meshed with both the ring gear and the sun gear, a rotational axis of each said planet gear being fixed with respect to the driving member;   wherein the driving member, the planetary gear set, and the spool driving shaft are arranged so that rotation of the driving member through a given angular displacement causes rotation of the spool driving shaft through an angular displacement greater than that of the driving member.   
     
     
       7. The film winding mechanism as recited in claim 6, wherein the driving member comprises a manually operable rotary knob disposed entirely outside of the main body of the lens-fitted film unit. 
     
     
       8. The film winding mechanism of claim 7, further comprising a top boss disposed on an end of the sun gear opposite the spool driving shaft, the top boss being rotatably supported within an aperture disposed in a center of the rotary knob. 
     
     
       9. The lens-fitted film unit as recited in claim 7, wherein the planet gears are disposed at regular angular intervals, each of the planet gears being rotatable mounted on a carrier shaft disposed on a lower face of the rotary knob. 
     
     
       10. The film winding mechanism of claim 9, further comprising a top boss disposed on an end of the sun gear opposite the spool driving shaft, the top boss being rotatably supported within an aperture disposed in a center of the rotary knob.